As computer systems evolve, many different kinds of tasks are performed using computers; however, when compared with the human brain, computer systems excel in certain areas but come up short in other areas. For example, a computer can perform many mathematical calculations in a very short period of time when compared with a human brain; however, a human child learns very early to recognize his mother's face in a crowd of people. Such face recognition is difficult for computer systems, requiring complicated algorithms and large amounts of processing power. When considering that the human brain can effectively operate at a frequency of about 40 Hertz and central processing units of modern computer systems can operate at frequencies exceeding one Gigahertz, the disparity seems larger. By reproducing some of the processing methods of the human brain, electronic circuitry and computer systems may be able to perform tasks, such as pattern recognition, more efficiently and effectively.
Parts of the human brain have been modeled using electronic circuits for a number of years. In particular, certain neural behaviors can be somewhat reproduced with controllable oscillators and phase-locked loop circuits or, in the mechanical world, with pendulums; however, phase-locked loops have acquisition or lock times that may hinder the effective speed of circuits relying on locking behavior of phase-locked loops. Thus, there is a need for electronic circuitry using controllable oscillator circuitry, which stabilizes quickly and mimics the human brain when processing information.